In previous work , we have developed techniques for studying the chemical and rheological properties of tracheal mucus, available from the canine tracheal punch model. We propose to further study the relationship between the chemical composition and macromolecular structure of respiratory mucus with the aim of elucidating the role of such chemical moieties as sialic acid, oligosaccharide side chains and crosslinking agents in determining the rheological proerties of the mucus and its ability to maintain normal mucociliary transport. Mucus from both normal animals and animals modified by such treatment as sulfur dioxide exposure will be studied. The results should lead to a better understanding of the physico-chemistry of mucociliary flow and its important role in obstructive pulmonary disease. Methods will include use of the magnetic microrheometer and a reconstitution procedure for mucus developed in our laboratory, chemical techniques modified for use with respiratory mucus, and the frog palate model for studying mucociliary transport.